It is known that human's vocal cords are located in the larynx. For that reason, the aim of laryngoscopy is to examine the general state of the vocal folds, detecting from a simple failure in the production of sounds to tumors and other serious anomalies. However, in many larynx examinations, an accurate visualization of the vocal folds function with the naked eye is impaired due to the depth to which this organ is located, as well as the high frequency vibration of these vocal folds when sounds are produced.
A variety of attempts have been made to perform this examination. One method has been to connect laryngoscopes to video cameras. However, due to the large size of these cameras, it was necessary to use a thin metal tube (called “optics tube”), with internal lenses that transmit image of the larynx to the camera's image sensor. These so-called video laryngoscopes, visualize the larynx by means of a camera, and display the final image upon a TV monitor.
However, in order for specialized physicians to assess accurately the general state of the vocal folds, is not simply enough to visualize the larynx, it is necessary to test the vocal cords. Asking the patient to produce sounds on several frequencies, while the physician observes the behavior of the vocal folds does this testing.
The human eye however, is not capable of capturing images at frequencies higher than 30 Hz (30 cycles per second). Above this frequency, the human eye loses its ability to observe one movement at a time, and it is impossible to perceive how the vocal cords work. This phenomenon is similar to the phenomena, which takes place when a party looks at the blades of a spinning fan. It is not possible to follow a single fan propeller blade separately. The velocity of the spinning of the blade causes the blade to appear as a single disk due to the human eye. This is because the rate at which the blade spins is significantly faster than the rate at which the human eye can perceive and process this information.
The solution to this problem was found to be the implementation and use of a second resource to the laryngoscopes, a stroboscopic light. Stroboscopy is a method of illumination where the light turns on and off at varying velocities (hundredth of seconds) providing frequency offset. This type of light is generally used in discotheques, which provides, for example, an intermittent aspect to the body movements. These apparent jumps between movements from one position to another solve the problem of the human eye not to see movements at high frequency. In the case of the use in discotheques, body movements look like “broken” because such movements are very slow for the use of such light source.
In the case of a stroboscopic illumination of a turned-on fan, for example, it is possible to follow a propeller blade rotating with very slow movements, when actually it is rotating at high speeds, which are invisible to the human eyes with a constant light. It was this application (to be able to see a movement in slow motion) that was adapted to the video-laryngoscopy.
As in the case of the cameras, the stroboscopic light source presents a large extreme size, which makes impossible to introduce it into the oral cavity of the patient. The solution found was the use of a fiber optic cable that directs the source light beam to the optics tube. In this way, it was possible to illuminate the larynx with a stroboscopic light source, transforming the high-frequency movements of the vocal cords in slow-motion movements, which makes possible to be accurately analyzed by physicians. This examination that started to use the stroboscopic light source is called “videolaryngostroboscopy”.
Around the world, there is high incidence of larynx cancer. When detected at its early stage, the probability of cure of this type of cancer is increased to near 100%. The importance of the videolaryngostroboscopy lies in the fact that this is the single examination used in the diagnosis of this type of cancer.
The existing videolaryngostroboscopes available in the market use similar methods of image capture. Its functioning is based on the image capture of the larynx by means of an optics tube that is connected to a camera and a fiber optic cable, which allows it to illuminate and film the vocal folds.
If a common videolaryngostroboscope were separated in isolated items, we would have:
1. Video camera, generally a high resolution video camera;
2. Stroboscopic light source equipped internally with a xenon gas-filled lamp, which pulses at frequencies determined by the patient's voice or by the physician;
3. Optics tube: a metal tube generally made of stainless steel, with about 1 cm in diameter and 30 cm in length. It has the function of being inserted into the patient's oral cavity, providing illumination to the larynx and transferring the images captured by its internal lens to the camera's image sensor, at the other end;
4. Coupler: since the optics tube does not have a screw-type attachment system to be fastened to the camera, a coupler is nothing more than an adapter that attaches the optics tube to the camera;
5. Fiber optic cable: this cable directs luminous beams from the stroboscopic source to the optics tube, and;
6. Frequency sensor: a microphone used to capture the voice frequency of the patient.
7. Auxiliary pedal: during the examination, it allows the physician to control the speed of slow motion effect.
In this way, specialists who use traditional videolaryngostroboscopes in their performance area have to purchase each one of the above mentioned items separately, which are frequently made by international manufacturers, thereby incurring high costs to acquire each item and damages related to the warranty of these products.
Furthermore, traditional videolaryngostroboscopes, which utilize high cost items such as xenon gas-filled lamps and fiber optic cables, are typically high in cost and large in size. This causes to produce to be expensive and limits the portability of these items to various other locations. Consequently, it makes impossible the use of these items to provide medical assistance in diversified places such as streets, or remote locations, thus resulting in higher number of persons who cannot be treated by such a device.
In addition to these presented disadvantages, additional disadvantages that are present in devices that are currently in use include were also identified in by a meticulous analysis of traditional videolaryngostroboscope models, as follows:                It is uses xenon gas-filled lamp, which produces waves ranging from 6400K to 8000K and, consequently, color distortions are generated on the video monitor, resulting in a bluish image;        The light-emitting element is located at the external light source, which disturbs the professional who operates the apparatus, since easy-handling and practicality requirements are not being met by traditional videolaryngostroboscopes. Also, said light-emitting element has a lifetime of only 500 hours.        The camera is located external to the apparatus and connected to the optics tube by means of an adapter. So, it is necessary to purchase it separately, thus raising product prices.        Additionally, for this type of light-emitting element, it is necessary to use a light bulb, whose replacement is expensive, since it is an imported light bulb, and its price is in dollar.        The method for emitting light from the source to the optics tube is made via fiber-optic cable, thereby incurring high costs to acquire it, since it is sold separately.        Another adverse factor of traditional videolaryngostroboscopes is related to the fact that said optics tube has to be coated with stainless steel, which is a cold material and frequently causes nausea and discomfort to the patient, because it will be in contact with the patient's throat.        Besides other negative aspects that were identified, it is important to point out that:        Traditional videolaryngostroboscopes do not have an anti-fog system for the lens;        Traditional videolaryngostroboscopes do not have a coating for the optics tube, and;        As said traditional videolaryngostroboscopes are a combination of several pieces of equipment, their minimum weight is about 5000 g, which makes almost impossible to transport them and thus to provide care for out-patients.        
Due to the fact that it uses the aforementioned functioning methods, traditional videolaryngostroboscope model incurs high production costs.